Frequency changer



Feb. 28, 1933. L. LEVY FREQUENCY CHANGER Filed Oct. 29, 1928 Patented eb. 28, 1933 UNITEDSTATES' 'LUCIEN LEVY, or raarsmnancn V FR QUENCY camera ,Applicatio ninled October 29,1928; serial No. 315,843, and in France June 4, 1927-.

: Applications for this invention have been filed in France, June 4, 1927, and October 22,

' ."My invention relates to a frequency changer designed primarily for receiving wireless waves by the superheterodyne'method.

like theone disclosed in my prior application N SierrNoJ 280,354 fi1ediMay 24, 1928, and entitledElectron discharge device, and the invention relates to new ways of connecting the electrodes of said tube with different circuits order :to obtain a frequency changer operating under'better conditionsthan does the one described in my prior application. On the accompanying drawing:

Fig.1 is a characteristic curve representing the operation of the vacuum tube.

Figs; 2 to 4 show Wiring diagrams according to the invention, r r 5 The vacuum tube is comprised of a bulb 1 (Figs. 2, 3, or 4) inside which a vacuum is produced, and containing'a cathode 2 consti tuted by a filament heated by'a battery 3, an anode 4, a grid 1 0, and an auxiliary electrode 6 placed at the opposite side of the cathode from the anodeand nearer to saidcathode 2 than is the anode'platelif V g r "If, in said vacuum tube, suitable potentials with reference tothe' cathode 2:a're impressed V on the grid 10 and on the anode 4, and if the potential of the auxiliary varies with reference to 'said'cathode 2, the current flowing between thefcathode 2 and the anode 4 will also vary, since the auxiliary electrode '6,owing to its close proximity to the cathode, has a great infiuence on the space charge and can,eithe'r, if its potential is negative and of sufficiently great value, prevent the electrons from flowing from the filament, or attract to itself all the'electrons, if its potential is positive and of sufliciently greatvalue, vConsequently, the curve representing the anode current I plotted against the potential V of the auxiliarylelectrode will be asymptotic to the axis of the abscissae and will 'be'shaped asshown in Fig. 1.

alt is obvious that said curve depends onthe e potentials impressed on the grid and on the electrode, 6'

general shape always remains a a very great variation ofthe anode current, This frequency changer uses a vacuum tube.

this can be seen on the characteristic curve plotted inFig. 1, wherein the two branches AB and BC are greatly inc-lined onthe axis oftheabscissae. Inyconsequen'ce'the efl'ect of the auxiliary electrode may be considered as a relay efi'ectsimilarto that of a grid. Ifnow, under such conditions, we impress on the auxiliary electrode a potentialsuch that the corresponding'point on the'charac- C5 teristic curve be on thedescending branch BC, and if said auxiliary electrode'is connected to the anode circuit in' such manner that an increase of the anode'current tends'to increase the potential of theauxiliary electrode, the anode current will oscillateat a r r frequency depending on the particular tea tures of the device. "j

Oscillations may also be obtained if the point which is representative of the operation. is on the ascending branchAB' of the 1 characteristic curve, to accomplish that end,

it is "suflicient toreverse the connections of the auxiliary elect-rode and 'the'plate circuit,

' in such manner that the potential of the aux-f iliaryelectrode 6 hasla tendency todecrease,

While the anode current increases.

Variations of the grid potential may a overlaid upon thosecreated in the above dis closed *manner, and the beats produced by I interference of these oscillations can'be selected, the device thus really operating as a frequency changen. I v I I 1 Fig. 2 show s a wiring diagram of a frequency changer using the descending branch BO of the" characteristic curve. The grid 10 byian inductance coil-26 and a'condens er-connected in parallel, and tuned to a frequency F,

2. A second oscillating circuit 18 tuned to the frequency FF and which can be connected to or coupled with a receiving set 19 of any suitable type,

' pole of which is 3. Abattery 5, the positive pole of which is connected with the anode 4.. i

The auxiliary electrode 6 s connected with the positive pole of a battery 7, the negative 7 diate point 25 of the inductancecoil26 of the first oscillating circuit. The battery 7 impresses on the auxiliary electrode 6 a positive potential such that the representative point willbe on the branch BGof the characteristic curve, its abscissze being for instance 8, as shownin Fig. -1.

l correspondingnumerals .of Fig. 2 have been connections of employed for indicating the same elements of the device. In the diagram shown, the the oscillating circuit 11 with the wires-leadingto the control plate and. to

i the filament are modified; on Fig. 3 the con-s trol circuit is connected at 25 with the end of the induction coil 26 ofthe circuit 11; the wire closing this latter circuit, and to which the anode-filament circuit connects at 2 7, bein-g connected with apoint disposed towards the middle of the induction'coilr 011 Fig. l on the contrary the point .27. through' whichtheacircuit 11 is connected with the filament is towards the middle of the induction coil 26 and the point 25 connecting the the plate oscillating and control circuits is disposed on the wireinserted-in the latter circuit and leading as in Fig. 3 to the end of the induction coil 26.

What I claim is: I

1. An electric wave frequ'encychanger comprising a vacuum tube, comprised of a cathode, a grid, a plate, and an auxiliary cathode placed at the opposite side of the'cathode from andnearer to said cathode than is the plate; an input circuit for said tube con nected to the grid and cathode, said input circuit having means for impressing thereon oscillations at a frequency F; an output cir- 1 cuit forsaid tube including a first circuit oscillating at a frequency F asecondoscillating circuit tuned to the difference frequency F'-.F', and a source .of direct current, all connected in -series; and means for coupling the connected with an inter ine connected to the grid and cathode,

said auxiliary electrode of the vacuum tube with the first oscillating circuit in such manner that thevariations of potential of said auxiliary electrode are shifted With the current variation, in order to generate oscillations at the frequency F in the first oscillatory circuit. I

2. An electric U QOlTIPI'ISlHg a vacuum cathode, a grid, a plate,

wave frequency changer, tube comprised of a and an auxiliary electrode 'placedat the opposite side-0f the oathodefrom the plate and nearer to said cathode than the plate; an input circuit for said tube connected to the grid and cathode, said input having means for impressing'fthereon oscillations at a frequency F; an outputcircuit for said tube including a -firstcircuit oscillating at the frequency F, the said first oscillating,circuit-comprising an inductance coil and capacitance in parallel, a secondscircuit tuned to the difference frequency F-F-,'and

a source of Kdirectcurrent potential, the positive pole of which is connected to the plate,

all connected in ser-ies; and 'a' second source of direct current potential, the positive pole of which is connected tothe auxiliary elec-; trode and the negative, pole of which is connected to an intermedi ate point of; the said inductance coil of the first oscillatory circuit,

3. .An electric :wave frequency changer, comprising a, vacuum tube comprised of a cathode, a grid, a plate, andan auxiliary electrode placed at the opposite side-of the cathode from the plate and nearer to the said cathode than the plate; an input circuit for said tube connected to the grid and cathode, said input circuit having means for impressmoo ing thereon oscillationsfat a frequency .F ;'and

an output-circuit forsaidtu-be includin afirst circuit oscillating at the frequency F, the said first oscillatory circuit comprising an inductance coil and a capacitance in parallel; .a-

second circuit tuned to the difference frequency and a sourcebf dire'ct current potential all connected inseries the auxiliary electrode being connected to a point-intermediate of the first and second oscillatory circuits, said auxiliary circuit-including an inductance coupled to the said inductancecoil of the first oscillatory circuit, the inductance coil of said first circuit havingoneend connected to, the auxiliary electrode and an inter mediate point connected to thesecond oscillating circuit. 7 v

4. An electric wave frequency changer, comprising a vacuum tube comprised of a cathode, a'grid, a plate,'and an auxiliary elec trode placedat the opposite side of the oath od'e from the plate and nearer to said cathode than the plate, an input circuit for said tube said input circuit "having means for impressing thereon oscillations at afrequency F; an output c rcuitfor said tube including :a'first circuit os-' lating circuit having an inductance coil and a capacitance in parallel, a second oscillating circuit tuned to the difl'erence frequency F -F, and a source of direct current potential, the positive pole of which is connected to the plate, all connected in series; means for connecting the second oscillating circuit with the cathode and with an intermediate point of the inductance coil of the first oscillating circuit, and means for connecting said first circuit on one side thereof with thegnegative pole of the source of direct current potential and on the other side with the auxiliary electrode.

In testimony whereof I have signed my name to this specification.-

LUGIEN LEVY. 

